Private doctors expect to be fully booked for Caesarean sections on December 12 this year - or 12/12/12, the last triple such date of the century and a day some couples consider lucky or auspicious.

But doctors advise against opting for a Caesarean section over a natural birth just for the sake of choosing the baby's birthday. They say there is still a risk to the health of mother and baby from surgery, despite advances in medical technology.

Fung shui master Mak Ling-ling said 12/12/12 was not a particularly lucky day from a geomantic point of view. The fung shui literature did not indicate it was a favourable date for giving birth, she said.

In fact the prediction is that babies born that day will be emotional and tense, although they will excel in academic work.

Obstetricians said couples who want to have a chance of having a baby born on 12/12/12 will have to conceive by the end of this month.

Although in vitro fertilisation can increase the chance of pregnancy, Emily Lam Po-mui, a specialist in obstetrics and gynaecology, said couples should not rely on that technology as a means of controlling the birth date.

Its success rate among women aged 35 to 40 is only about 30 per cent, she said, and it may require several attempts.

Lam said it is too early to make bookings for delivery in December. But she expects bookings for Caesarean sections on December 12 to fill up earlier than usual, based on her experience of two similar 'auspicious' dates, November 11, 2011 and October 10, 2010.

Dr Leung Tak-yeung, professor of obstetrics and gynaecology at Chinese University, said he would not encourage expectant mothers to deliver by Caesarean section on a date they had chosen.

'It is surgery and bears risks. And it is important that the term of pregnancy is complete, to avoid premature delivery,' he said.

If the woman's menstrual period came between March 5 and 25, and conception took place two weeks afterwards, then it would be possible for the baby to be born on December 12, Lam said. She said this assumed that the expectant mother had a regular menstrual cycle.